It's just larger than your SFR, 2U, and Quads you described with different lending parameters.That being said, it is not uncommon for a small, mom & pop, operator to have terrible books. 

I do not think this is a one size fits all answer and there are times where private lending is preferred over traditional financing.

Thanks Ned, Short answer to explain it, I did not know they were around back then, just found out now when we are coming back, a little background, when I started in 2005, I was a child :) 28 years old and thought I knew it all, all, all :), did not know about hard money lending, only new about bank loans, and Home equity lines of credit, did not know where to find more money, since I did not have much, I would rely on what I could get from banks, loans, credit cards and was not always that great, it was a learning experience.....and Wholesalers, I did not know that even existed, everything I would find back then was already on the market and through a "friend" agent, MLS, FMLS and all those, nothing like what we have today.

You can raise cash via debt or equity and via institutional or private means.

If you're interested, I can point you in the direction of a few potential lending options that might be a good fit for your situation.

How can a 20th-year-old approach commercial loan officers and investors to lend the money to invest in a 8 or 10-unit apartment?

Will someone lend me money to pay off another hard money loan?

You wire funds to a company that is in the business of building buildings, they create plans, get permits, raise additional capital, supervise construction, supervise filling the building with tenants, sell the building to an institutional investor, and if everything has gone to plan then there will be a significant profit and they wire you back more money than you put in.

I did a private lending , borrower bought house under the name of LLC, first lien recorded. value of house is at least to cover the loan(as of now).

Just some food for thought.Typically from my experience, a lender that is willing to do a "blanket" style loan, lends from their own portfolio.